SUPRA SA, Piggyback Ballast and Autowake

Hi, I'm considering a 2021 Supra SA. I'm interested in maxing out the ballast, specifically by adding a single u-shaped bag under the front bow seats, with a pair of bags equaling that front weight in the two rear lockers.for example, if that front bag is 600 pounds, I'd install a 300 pound bag in each rear locker to ensure equal piggyback weight throughout the boat.

In my research I understand there is a draft sensor that may prevent putting too much weight in the boat, along with ballast pumps that stop when capacity has reached 100%. With this said, I'm looking to better understand the ballast system so I can accomplish my goal.

1. How are ballast levels measured? Do the ballast pumps have timers that can be adjusted so I can reach 100% once the stock and piggyback bags have reached max capacity?

2. Regarding the draft sensor, is there a certain amount of weight in the boat that is reached in order for the draft sensor to max out? Can this setting be adjusted?

3. What does the plumbing and pump configuration look like? Are these reversible pumps to fill and drain? Are there vent hoses?

Any suggestions would be greatly appreciated. This is an impressive boat and I'm looking forward to massive surf wakes. Thank you.

Pumps are reversible and on adjustable timers and have overflows.

You are adding 1200# of weight and that is still within the 2400# of passenger rating, so draft sensor should still be within range.

I believe the subfloor ballast are bags and the plumbing should be the same as any piggy back set up. Wake makers may already have a kit for the subfloor Supras.

My suggestion would be using leadwake and you don’t need more than 500-700#


Sent from my iPhone using Tapatalk

I agree. Most of the SAs that I've ridden have around that 500# of lead weight and most of it is behind the tower seating area to get the correct pitch.

Not saying 1200#s is bad or do not do it, another factor is the size of your crew. Sounds like you have been reading up on the SA. Great boat.

I have a buddy in Knoxville that just installed two 400# bags in this SL. He has been using lead for a few years, but wanted to try a solution of not having to tow around 800-1000# of lead if they were not surfing or had to tow the boat on land. He piggy backed into the one pump line on each side of the locker bag. Installed a manual shutoff value to open and close when needed. Each bag is also vented over the side.

For each side: Existing Pump Line > Y-Connection> Hose > Shut-Off Valve > Line to the Bag Under Seat. Vent line on the top of bag. Bags were 60x20x8.

Thanks for the feedback everyone.

So I've run lead in my current boat for years with success. However, with the SA, it's clearly got the space to add ballast so here is my justicationi for additional ballast:

- Better fuel economy when not riding
- Maintain all under seat storage in the main cabin which I prefer
- Better wake with less people

With that said, I do have one concern. The SA has dual pumps, and I believe just a single vent line. So, once the under floor ballast is full you would have two pumps trying to fill the above floor ballast bag through the single vent hose of the below floor bags, which is inefficient at best and perhaps a problem at worst. I thought I saw a post on the Moomba forum where Matt (goose?) from Skier's Choice mentioned you would need to purchase new bags with an additional vent line to properly piggyback with the dual pump setup. I get there are other ways to plump this, but to maintain the advantages of autowake the dual vents going to the piggyback bags would be ideal.

Does anyone know how I can add Matt to this thread for comment? Thank you!

Try to PM goose

Let us all know what you find, ordering a 21SA tomorrow.

I don’t think 500# of lead will hurt your cruising mpg too much. Unless you do a lot of 35mph cruising.

One of the main reasons I moved from an 18SA to a 21SA was it was all subfloor ballast. Lead just takes us such little space compared to a bag.

I don’t want a bow bag because I am so looking forward to putting the box anchor and 150 foot of rope under the hinged bow seats.



Sent from my iPhone using Tapatalk

LarryArizona has the same setup going in his 2021 SA as I do in the 2018 SL. I run 500-1000#s depending on how big my crew is for that day and Subfloor ballast is awesome. It was standard starting the 2018 SL redesign.

If you do not hear from Matt Brown, he may have his contact info on the Moomba forum. I think I've seen an email posted somewhere. I know he did some good write-ups on the AutoWake feature - might try there. The threads are long, so you need to budget time to get through them - not a 2-5 min read.

Over the years, I have not read about any issues with 2 pumps and 1 vent line.

I started to do a write-up about what each of the 10 water outlet ports are on the Supra SA and how you might get a piggy back system in the front and rear to best function. Then I started reading some of posts describing some of the Moomba ballast technologies like water sensors and air release valves and started to question my analysis of what Supra is actually doing.

I'm confident I can make this system work well, and I think it would be a fun challenge, but it's possible some ports may need to be added to the stock ballast bags in order to accomplish this. What's clear is I need to either dig through an SA first-hand, or ideally talk to someone to Skier's Choice with intimate knowledge of how the system works.

I've asked my dealer if they can put me in touch with someone at Skier's Choice. More info to come. Thanks.